One-way clutch integrated with a rolling bearing, and method of producing the same

ABSTRACT

In a one-way clutch integrated with a rolling bearing, rolling elements and sprags are arranged in an annular space between an inner race and an outer race in each of which a one-way clutch raceway surface is formed in one axial side of a rolling bearing raceway surface. The rolling elements and the sprags make contact with respective raceway surfaces and are respectively housed in circumferentially spaced pockets formed in a common cage configured by mutually engaging and integrating two annular members in an axial direction. The one-way clutch includes urging means for urging the sprags in a locking direction in the pockets. An annular flat plate portion which seals one axial end portion of the annular space between the inner race and the outer race is integrally formed in one of the two annular members constituting the cage. Respective at least one radial and axial through holes are formed in the annular member.

REFERENCE TO RELATED APPLICATION

This is a divisional application of Ser. No. 10/828,987, filed Apr. 21,2004 which is currently allowed. The subject matter of theaforementioned prior application is hereby incorporated herein byreference.

FIELD OF THE INVENTION

The invention relates to a one-way clutch integrated with a rollingbearing which is configured by integrating a sprag one-way clutch with arolling bearing.

BACKGROUND OF THE INVENTION

Usually, a one-way clutch integrated with a rolling bearing has astructure in which a sprag one-way clutch is disposed on one or bothaxial sides of a rolling bearing such as a rolling bearing, and theinner and outer races of the rolling bearing are integrated with thoseof the one-way clutch, respectively.

In such a one-way clutch integrated with a rolling bearing, in order tofacilitate assembling and enhance compactness, various countermeasuresare taken mainly on a cage.

FIG. 14 is a partially cutaway front view of an example of aconventional one-way clutch integrated with a rolling bearing in which asprag one-way clutch is disposed on both axial sides of a ball bearing,FIG. 15 is an axial section view of the example, and FIG. 16 is anexploded perspective view of a cage and a spring and side plate.

In this example, ball bearing raceway surfaces 61 a and 62 a are formedin axial center portions of an inner race 61 and an outer race 62,respectively. One-way clutch raceway surfaces 61 b and 61 c, and 62 band 62 c are formed on both sides of the ball bearing raceway surfaces.A plurality of balls 63 serving as rolling members are rollably arrangedbetween the ball bearing raceway surfaces. A plurality of sprags 64 arearranged between the one-way clutch raceway surfaces which are on bothsides of the ball bearing raceway surfaces. The balls 63 and the sprags64 are held at predetermined intervals in the circumferential directionby a common cage 65 which is configured by engaging and integrating twoannular members 651 and 652 with each other in the axial direction.Spring and side plates 66 in each of which plural spring pieces 66 a forrespectively urging the sprags 64 in a locking direction are formed onthe outsides of the sprags 64 are fixed to the annular members 651 and652 constituting the cage 65, respectively.

In the two annular members 651 and 652 constituting the cage 65,recesses 651 a and 652 a which, under a state where the members areengaged with each other, configure pockets for housing the balls 63 inthe center portion are formed in one axial end side and at constantintervals in the circumferential direction, and pockets 651 b and 652 bfor housing the sprags are formed in the opposite end side. In one ofthe two annular members 651 and 652, or the annular member 651, a claw651 c which elongates in the axial direction is formed in pluralpositions along the circumferential direction. In the other annularmember 652, plural recesses 652 c with which the claws 651 c are to befittingly engaged are formed.

The thus configured one-way clutch integrated with a rolling bearing isassembled in the following manner. A required number of balls 63 areinserted and arranged between the inner race 61 and the outer race 62and at approximately constant intervals in the circumferentialdirection. Thereafter, the annular members 651 and 652 are insertedbetween the inner race 61 and the outer race 62 so as to sandwich theballs 63 from the both sides in the axial direction. The claws 651 c arerespectively inserted into the recesses 652 c so as to be engagedtherewith, whereby these members are integrated with each other. Anundercut is disposed in each of the claws 651 c and the recesses 652 c.As shown in FIG. 17 which is an enlarged axial section view showing anengagement state, an inclined face 651 d is formed in the tip end sideof each of the claws 651 c, and an engaging portion 651 e is formed inthe basal end. An engaging portion 652 d which is to be engaged with theengaging portion 651 e is formed in each of the recesses 652 c. Becauseof the engaging portions 651 e and 652 d, in an assembling process, theannular members 651 and 652 can be easily engaged with each other bysnap fit, and, after assembling, the engagement state is prevented bythe engagement of the engaging portions 651 e and 652 d from beingeasily cancelled (for example, Japanese Patent Publication (Kokai) No.2000-304068 (pages 2 to 4, and FIGS. 2, 3, and 7)).

As a structure in which a sprag one-way clutch is disposed on one sideof a rolling bearing, also a configuration is known in which a cage fora rolling bearing is axially integrated with that for a sprag in theaxial direction via an engagement mechanism (for example, see JapanesePatent Publication (Kokai) No. HEI11-72127 (pages 3 and 4, and FIGS. 4to 9)).

Usually, a one-way clutch integrated with a rolling bearing which isconfigured by integrating a rolling bearing such as a ball bearing witha sprag one-way clutch is structured in the following manner. Asexemplarily shown in an axial section view of FIG. 18, rolling bearingraceway surfaces 41 a and 42 a are formed on an inner race 41 and anouter race 42, respectively, and plural rolling members 43 are rollablyarranged between the raceway surfaces. In the inner race 41 and theouter race 42, one-way clutch raceway surfaces 41 b and 42 b are formedin parallel with the rolling bearing raceway surfaces 41 a and 42 a,respectively. A plurality of sprags 44 are arranged between the one-wayclutch raceway surfaces. The rolling members 43 and the sprags 44 arearranged by a common cage 45 at constant pitches in the circumferentialdirection in an annular space formed between the inner race 41 and theouter race 42. Each of the sprags 44 is urged in a locking direction byurging means such as a garter spring 46.

As shown in the figure, usually, the sprag raceway surfaces 41 b and 42b of the inner race 41 and the outer race 42 are usually formed asextended faces of shoulder portions 41 c and 42 c of the rolling bearingraceway surfaces 41 a and 42 a, or so as to have the same diameters asthose of the shoulder portions 41 c and 42 c.

In a sprag one-way clutch, as the J space which is the distance betweenthe raceway surfaces of inner and outer races is larger, the size ofuseful sprags can be made larger so that the performance including thetransmission torque can be improved. In the conventional one-way clutchintegrated with a rolling bearing shown in FIG. 18, the diameters of thesprag raceway surfaces of the inner and outer races are respectivelyequal to those of the shoulder portions of the rolling bearing racewaysurfaces, and hence the size of the J space is approximately constant inaccordance with the model number (size) of the rolling bearing to beintegrated. Therefore, improvement of the performance of a one-wayclutch is limited.

In order to widen the J space as compared with a conventional one-wayclutch integrated with a rolling bearing to improve the performanceincluding the transmission torque, the inventors proposed a one-wayclutch integrated with a rolling bearing in which, as shown in an axialsection view of FIG. 19, a step 510 is formed between a shoulder portion51 c adjacent to a rolling bearing raceway surface 51 a and a one-wayclutch raceway surface 51 b, for one of an inner race 51 and an outerrace 52 (in FIG. 19, the inner race 51), whereby a larger J space can beensured (see Japanese Patent Publication (Kokai) No. 2000-291651). FIG.19 exemplarily shows a one-way clutch integrated with a rolling bearingof the type in which rolling elements (balls) 53 of the rolling bearing,and sprags 54 of the one-way clutch are held by dedicated cages 55 and56, and a spring member 57 wherein a plurality of spring pieces 57 b areformed integrally on an annular base member 57 a is used so that thesprags 54 are urged in the locking direction by the spring pieces 57 b(Japanese Patent Publication (Kokai) No. 2000-291651 (pages 2 to 4, andFIG. 1).

In the proposed one-way clutch, the race in which the step is formed isdetermined so as to be that on the side of one of fitting counterparts Sand H which has higher shape accuracy of the fitting surface, wherebyaccuracy of the race in which the thickness of the portion where theone-way clutch raceway surface is formed is reduced by the formation ofthe step can be prevented from being lowered in accordance with thecounterpart as a result of the fitting.

Usually, a one-way clutch integrated with a rolling bearing which isconfigured by integrating a rolling bearing such as a rolling bearingwith a sprag one-way clutch has the following structure. As exemplarilyshown in FIG. 14 which is a partially cutaway front view, and FIG. 15which is a section view taken along the line A-A in FIG. 14, the rollingbearing raceway surfaces 61 a and 62 a are formed on the inner race 61and the outer race 62, respectively, and the rolling members 63 arerollably arranged between the rolling bearing raceway surfaces. In theinner race 61 and the outer race 62, the one-way clutch raceway surfaces61 b and 62 b, and 61 c and 62 c are formed in parallel with the rollingbearing raceway surfaces 61 a and 62 a, and the sprags 64 are arrangedbetween the one-way clutch raceway surfaces.

The rolling members 63 and the sprags 64 are held in an annular spaceformed between the inner race 61 and the outer race 62, at constantpitches in the circumferential direction by the cage 65 which iscommonly used in this example. In this example, the cage 65 has astructure in which the two annular members 651 and 652 are integratedwith each other in the axial direction, and comprises pockets for therolling members 63 and those for the sprags 64. The rolling members 63and the sprags 64 are housed in the pockets so as to be arranged atconstant pitches in the circumferential direction. The sprags 64 areurged in the locking direction by the spring and side plates 66 in eachof which plural spring pieces 66 a are formed on the annular base member66 b (for example, Japanese Patent Publication (Kokai) No. 2000-304068(pages 2 to 4)).

In such a one-way clutch integrated with a rolling bearing, lubricationis conducted by grease, and hence the space between the inner and outerraces is filled with grease. In the a one-way clutch integrated with arolling bearing disclosed in Japanese Patent Publication (Kokai) No.2000-304068, therefore, the spring and side plates 66 which are disposedin the axis end portions exert a function of preventing grease fromleaking.

Since the two annular members 651 and 652 constituting the cage 65 havethe claws 651 c or the recesses 652 c each having an undercut, holes forenabling molds to be extracted are required. In the annular members 651and 652, therefore, it is necessary to form axial through holes whichare indicated by H in the first annular member 651 of FIG. 16 (withrespect to the second annular member 652, the through holes are notshown in the figure, and are formed in positions where the recesses 652c are to communicate with the sprag pockets 652 b). The spring and sideplates 66 prevent the grease from leaking through the holes.

The mold extracting holes are used also as holes for filling the greasebetween the inner race 61 and the outer race 62. After one of the springand side plates 66 is attached and before the other spring and sideplate 66 is attached, the grease is filled via the axial through holeson the side where the spring and side plate 66 is not attached.Thereafter, the other spring and side plate 66 is attached. As a result,the workability of the assembly process including the grease fillingwork can be improved.

In order to reduce the production cost, the structure in which a one-wayclutch is disposed on one side of a rolling bearing is more advantageousthan that in which a one-way clutch is disposed on both sides of arolling bearing. In the case where the above-described technique ofJapanese Patent Publication (Kokai) No. 2000-304068 in which two annularmembers are axially engaged with each other by an engagement mechanismincluding an undercut is applied to a structure in which a one-wayclutch is disposed only on one side, a spring and side plate is attachedonly to the one side where the one-way clutch is disposed. Therefore,grease on the other side must be sealed by additionally disposing adedicated side plate or the like.

It is an object of the invention to provide a one-way clutch integratedwith a rolling bearing which has a structure where a one-way clutch isdisposed on one side of a rolling bearing, and in which a side plate orthe like for preventing grease from leaking is not required on the sidewhere the one-way clutch is not disposed, the workability of theassembling process including a grease filling work is excellent, and thegrease can be satisfactorily distributed over the raceway surfaces ofinner and outer races.

As a result of the proposal in Japanese Patent Publication (Kokai) No.2000-291651, the J space can be widened as compared with a conventionalone-way clutch integrated with a rolling bearing of the same kind. Therace in which the step is formed can be determined so as to be that onthe side of one of fitting counterparts which has higher shape accuracyof the fitting surface, so that reduction of the accuracy of the one-wayclutch raceway surface due to a reduced thickness can be prevented fromoccurring during fitting. However, reduction of the thickness isnaturally limited. This causes a bottleneck in a countermeasure in whichthe J space is widened to increase the size of sprags.

It is an object of the invention to provide a one-way clutch integratedwith a rolling bearing in which the J space can be further widened ascompared with the above-mentioned proposal, so that larger sprags can beused, and which is therefore small in size and produces a largertransmission torque.

As a result of the proposal, the J space can be widened as compared witha conventional one-way clutch integrated with a rolling bearing of thesame kind, and the performance including the transmission torque can beimproved. In the case where the proposed technique is applied to aportion where the space between a shaft and a housing is small and athin rolling bearing is used, however, the J space is limitedly ensured.

In a one-way clutch integrated with a rolling bearing, sprags in alocked state transmit a torque while being locked between inner andouter races. Therefore, the fitting of the inner race to the shaft, andthat of the outer race to the housing must be tight at a degree which ishigher than a certain level. If not, there arises the possibility that,in a locked state, a slip occurs between the inner race and the shaft orthe outer race and the housing. Consequently, a large assembly load mustbe applied to both the shaft and the housing, and the workability of theassembling process is not excellent.

The invention has been conducted in view of such circumstances. It is anobject of the invention to provide a one-way clutch integrated with arolling bearing in which the J space can be widened as compared not onlywith a conventional one-way clutch integrated with a rolling bearing butalso with a one-way clutch integrated with a rolling bearing accordingto the proposed technique, so that, even when applied to a portion wherea thin rolling bearing is used, a J space of a sufficiently large sizecan be ensured and a large torque transmission ability can be exerted,and the workability of a process of incorporating to a shaft or ahousing can be improved.

In a rolling bearing, when an adequate gap is not formed between theraceway surfaces of inner and outer races and the outer peripheral faceof each rolling member, the rolling member does not roll in a desiredmanner, and hence the performance cannot be exerted. Particularly, aradial gap which is a gap in a radial direction after assembly ischanged from that before assembly by deformation due to incorporation toa counterpart. Therefore, radial dimensions of the raceway surfaces ofthe inner and outer races are measured so that the gap in production, orthe so-called initial gap has a value in which a value corresponding todeformation due to fitting fixation of the inner race or the outer raceto a counterpart such as a rotation shaft or a bearing box isconsidered. A work which is called matching, and in which the size ofrolling members to be incorporated is selected in accordance with thedimensions is conducted. Thereafter, the assembling process isconducted.

By contrast, a sprag one-way clutch cannot exert the ability unless theJ space which is the radial dimension between the raceway surfaces ofthe inner and outer races for the one-way clutch is adequately held andthe radial gap with respect to a sprag is optimumly held.

In a one-way clutch integrated with a rolling bearing in which a rollingbearing is integrated with a one-way clutch, the inner race and theouter race are often incorporated into respective counterparts by aninterference fit. Therefore, the inner race is deformed in a directionalong which the diameter expands, and the outer race is deformed in adirection along which the diameter contracts, whereby, in a state wherethey are incorporated into respective counterparts, the J space iscorrespondingly narrowed. The reduction degree of the J space is varieddepending on the fitting to the counterpart and the dimensional accuracyof the counterpart.

In order to optimumly hold the J space after assembly, a conventionalone-way clutch integrated with a rolling bearing is processed in thefollowing manner. As shown in axial section views of FIGS. 20A and 20Brespectively showing only the inner race 61 and the outer race 62, thediameters ICD_(i) and OCD_(i) of the one-way clutch raceway surfaces 61b and 62 b of the inner race 61 and the outer race 62 are independentlycontrolled irrespective of the diameters IBD and OBD of the rollingbearing raceway surfaces, and processed into plural dimensions ICD_(i)(i=1, 2, 3, . . . ) and OCD_(i) (i=1, 2, 3, . . . ) in accordance withthe kinds of the counterparts to which the rolling bearing is to beincorporated, so that an initial J space corresponding to the kinds ofthe counterparts is obtained.

This causes the number of steps of inspecting and controlling thedimensions during a production process, and increases the productioncost.

The invention has been conducted in view of such circumstances. It is anobject of the invention to provide a method of producing a one-wayclutch integrated with a rolling bearing in which the number of steps ofinspection and control during a production process can be reduced ascompared with a conventional art and hence the production cost can belowered.

SUMMARY OF THE INVENTION

In order to attain the objects, the one-way clutch integrated with arolling bearing of the invention is a one-way clutch integrated with arolling bearing in which plural rolling elements and sprags are arrangedin an annular space between an inner race and an outer race in each ofwhich a one-way clutch raceway surface is formed in one axial side of arolling bearing raceway surface, the rolling elements and the spragsmake contact with respective raceway surfaces and are respectivelyhoused in pockets formed in a common cage, to be held at predeterminedintervals in a circumferential direction, the cage being configured byengaging and integrating two annular members with each other in an axialdirection, and the one-way clutch comprises urging means for urging thesprags in a locking direction in the pockets, wherein an annular flatplate portion which seals one axial end portion of the annular spacebetween the inner race and the outer race is integrally formed in one ofthe two annular members constituting the cage, at least one radialthrough hole which passes in a radial direction is formed in the oneannular member, and at least one axial through hole which passes in theaxial direction is formed in another one of the annular members (claim1).

In the invention, a configuration (claim 2) may be preferably employedin which the urging means has a structure in which plural spring piecesthat respectively urge the sprags are integrally formed in an annularflat plate member, and the urging means is attached to an axial outerside of the other annular member to cover the axial through hole,thereby sealing another axial end portion of the annular space.

In the invention, a configuration (claim 3) may be preferably employedin which each of the annular members constituting the cage is formed byan injection molded resin, and the axial through hole and the radialthrough hole which are formed in the annular members are mold extractingholes for forming an undercut disposed in an engagement portion betweenthe annular members.

According to the invention, a one-way clutch integrated with a rollingbearing having a structure in which a one-way clutch is disposed on onlyone side of a rolling bearing is provided with an excellent assemblyworkability based on the above-described technique of Japanese PatentPublication (Kokai) No. 2000-304068, and with functions of eliminatingthe necessity of a side plate for sealing grease on the one side, andallowing the grease between the inner and outer races to have anexcellent flowability.

In the configuration set forth in claim 1, the annular flat plateportion which seals one axial end side of the annular space between theinner and outer races is integrally formed in one of the two annularmembers constituting the cage, so that a side plate for sealing greaseis not required on the side of the annular member. The axial throughhole which passes in the axial direction is formed in the other annularmember, and hence grease can be poured after an assembling process.Since the radial through hole which passes in a radial direction isformed in the annular member in which the annular flat plate portion isintegrally formed, the grease poured into the space between the innerand outer races can easily flow.

As in the invention set forth in claim 2, a structure in which pluralspring pieces are integrally formed in an annular flat plate member isused as means for urging the sprags, and the structure is placed on theside of the annular member in which the axial through hole is formed,thereby sealing the through hole. According to the configuration, theside plate for sealing grease can be used also as the urging means, andhence it is possible to attain an effect that the number of parts can bereduced.

As in the invention set forth in claim 3, when the two annular membersconstituting the cage are made of an injection molded resin, the axialthrough hole and the radial through hole can be used as mold extractingholes for forming an undercut in an engagement mechanism.

In order to attain the objects, the one-way clutch integrated with arolling bearing of the invention is a one-way clutch integrated with arolling bearing in which plural rolling elements for a rolling bearing,and sprags for a one-way clutch are arranged in an annular space betweenan inner race and an outer race in each of which a one-way clutchraceway surface is formed on an axial side of a rolling bearing racewaysurface, with corresponding to the raceway surfaces, wherein, in each ofthe inner race and the outer race, a step is formed between the one-wayclutch raceway surface and a shoulder portion adjacent to the rollingbearing raceway surface, the step being directed in a direction in whicha radial dimension of the annular space in the one-way clutch racewaysurface is larger than a radial dimension of the annular space in theshoulder portion (claim 4).

In the invention, a configuration (claim 5) may be preferably employedin which an inner peripheral face of the inner race and an outerperipheral face of the outer race are fitted to respective counterparts,a radial thickness of a one-way clutch raceway surface forming portionof one of the inner race and the outer race is smaller than a radialthickness of a one-way clutch raceway surface forming portion of anotherone of the inner race and the outer race, the one of the inner race andthe outer race being fitted to one of the counterparts which has highershape accuracy of a fitting surface with respect to the inner race orthe outer race.

According to the invention, a step in the direction of widening the Jspace is disposed in both the inner race and the outer race, whereby theJ space can be further widened as compared with the case where a step isdisposed in one of the races (claim 4). In the one-way clutch racewaysurface forming portions of the inner and outer races, moreover, thesize of the step formed in the race on the side where the fittingportion of the fitting counterpart has higher shape accuracy is set tobe larger, whereby the effect due to the reduced thickness caused by thedisposition of the step is lessened as far as possible (claim 5).

In the invention set forth in claim 4, a step in the direction ofwidening the J space is disposed in both the inner race and the outerrace, whereby the room for widening the J space is increased and thedegree of freedom in design is improved as compared with the case wherea step is disposed in one of the races.

The steps of the inner and outer races are set so that the thickness ofthe one-way clutch raceway surface forming portion of one of the raceswhere the shape accuracy of the fitting surface of the counterpart issuperior is smaller than that of the portion of another one of theraces, whereby degradation of the shape accuracy of the one-way clutchraceway surface which is caused by the thickness reduction as a resultof deformation following to the counterpart in fitting to thecounterpart can be prevented from occurring.

In order to solve the problems, the one-way clutch integrated with arolling bearing of the invention set forth in claim 6 is a one-wayclutch integrated with a rolling bearing in which a sprag one-way clutchis integrally formed on a side of a rolling bearing, wherein a one-wayclutch raceway surface with which outer peripheral sides of sprags ofthe one-way clutch make contact is integrally formed on an axial side ofa raceway surface of an outer race of the rolling bearing, and innerperipheral sides of the sprags are to make contact with an outerperipheral face of a shaft which is to be fitted to an inner peripheralface of an inner race of the rolling bearing, thereby conducting torquetransmission between the outer peripheral face of the shaft and theone-way clutch raceway surface of an inner periphery of the outer race.

In order to solve the same problems, the one-way clutch integrated witha rolling bearing of the invention set forth in claim 8 is a one-wayclutch integrated with a rolling bearing in which a sprag one-way clutchis integrally formed on a side of a rolling bearing in the same manneras described above, wherein a one-way clutch raceway surface with whichinner peripheral sides of sprags of the one-way clutch make contact isintegrally formed on an axial side of a raceway surface of an inner raceof the rolling bearing, and outer peripheral sides of the sprags are tomake contact with an inner peripheral face of a housing to which anouter peripheral face of an outer race of the rolling bearing is to befitted, thereby conducting torque transmission between the innerperipheral face of the housing and the one-way clutch raceway surface ofthe inner race.

In the invention set forth in claim 6, a configuration (claim 7) may bepreferably employed in which an outer diameter of a portion of the shaftwith which the inner peripheral sides of the sprags are to make contactis approximately equal to an outer diameter of a portion to which theinner peripheral face of the inner race of the rolling bearing is to befitted. In the invention set forth in claim 8, a configuration (claim 9)may be preferably employed in which an inner diameter of a portion ofthe housing with which the outer peripheral sides of the sprags are tomake contact is approximately equal to an inner diameter of a portion towhich the outer peripheral face of the outer race of the rolling bearingis to be fitted. In the invention, the configuration in which the outerdiameters of two portions of a shaft or the inner diameters of twoportions of a housing are “approximately equal to each other” means thata step or the like is not intentionally disposed and a uniform outer orinner diameter is formed.

In the invention, “outer peripheral face of a shaft” includes not onlythe outer peripheral face of the shaft body but also that of anothermember which is fixed to the shaft body to substantially constitute asingle shaft member, and “inner peripheral face of a housing” includesnot only the inner peripheral face of the housing body but also that ofanother member which is fixed to the housing body to substantiallyconstitute a single housing member.

According to the invention, the outer peripheral face of the shaft orthe inner peripheral face of the housing is used as one of the inner andouter one-way clutch raceway surfaces, thereby attaining the objects.

In the invention set forth in claim 6, the one-way clutch racewaysurface with which the outer peripheral sides of the sprags of theone-way clutch make contact is integrally formed on the outer race ofthe rolling bearing in the same manner as a conventional one-way clutch,but only the rolling bearing raceway surface is formed on the inner raceso that the inner race is used substantially only for the rollingbearing. The inner peripheral sides of the sprags are not in contactwith the inner race but are in direct contact with the outer peripheralface of the shaft. According to the configuration, the J space can bewidened by a dimension corresponding to the thickness of the inner raceas compared with a conventional case where a one-way clutch racewaysurface is formed on the outer peripheral face of an inner race.

By contrast, in the invention set forth in claim 8, the one-way clutchraceway surface is integrally formed on the inner race of the rollingbearing in the same manner as a conventional one-way clutch, but onlythe rolling bearing raceway surface is formed on the outer race so thatthe outer race is used substantially only for the rolling bearing. Theouter peripheral sides of the sprags are not in contact with the outerrace but are in direct contact with the inner peripheral face of thehousing. According to the configuration, in the same manner as describedabove, the J space can be widened by a dimension corresponding to thethickness of the outer race as compared with a conventional case.

The outer diameter of the shaft portion with which the inner peripheralsides of the sprags are to make contact in the invention of claim 6, andthe inner diameter of the housing portion with which the outerperipheral sides of the sprags are to make contact in the invention ofclaim 8 are not particularly restricted. In order to solve theabove-discussed problems and employ a structure in which a conventionalone-way clutch integrated with a rolling bearing is simply incorporatedwithout providing the shaft or the housing with a special structure,i.e., a special structure due to the application of the invention, it ispreferable to, as in the invention of claim 7 or 9, set the outerdiameter of a portion of the shaft with which the inner peripheral sidesof the sprags make contact to be approximately equal to the outerdiameter of a portion which is fitted to the inner peripheral face ofthe inner race, or set the inner diameter of a portion of the housingwith which the outer peripheral sides of the sprags make contact to beapproximately equal to the inner diameter of a portion to which theouter peripheral face of the outer race is fitted. According to theconfiguration, the above-discussed problems can be solved, and theproduction cost of the shaft or the housing can be prevented fromrising, without affecting the other performances required in the shaftor the housing.

In order to attain the objects, the method of producing a one-way clutchintegrated with a rolling bearing of the invention is a method ofproducing a one-way clutch integrated with a rolling bearing in whichplural rolling elements and sprags are arranged in an annular spacebetween an inner race and an outer race in each of which a one-wayclutch raceway surface is formed axially adjacent to a rolling bearingraceway surface, wherein the inner race and the outer race are processedso that a radial dimension difference between the rolling bearingraceway surface and the one-way clutch raceway surface is within apredetermined tolerance with respect to dimensions that are setrespectively for the raceway surfaces, and the inner race and the outerrace are matched and incorporated so as to obtain an initial radial gapat which, in a state where the inner race and the outer race are fittedto respective counterparts, a radial gap of the rolling bearing has apreset value (claim 10).

In the invention, a method (claim 11) may be preferably employed inwhich, in the inner race and the outer race, the rolling bearing racewaysurface and the one-way clutch raceway surface are simultaneously groundby a form grinding process using a rotary dresser (claim 11). In theinvention, the dimensions of the one-way clutch raceway surfaces of theinner and outer races are not controlled, but, while using thephenomenon in which, when the inner race and the outer race areincorporated into respective counterparts, the degree of a dimensionalchange of the J space due to the dimensions of the counterpartsapproximately coincides with the degree of a change of the gap of therolling bearing, both the inner and outer races are processed so thatthe difference between the radial dimensions of the rolling bearingraceway surface and the one-way clutch raceway surface has the presetvalue, thereby attaining the objects.

In the invention, as indicated by an inner race 1 shown in FIG. 13Awhich is a view showing a fourth embodiment, and an outer race 2 shownin FIG. 13B, each of the inner race 1 and the outer race 2 is processedso that the difference between the diameter IBD or OBD of a rollingbearing raceway surface 1 a or 2 a and the diameter ICD or OCD of aone-way clutch raceway surface 1 b or 2 b has a value which ispredetermined for each of the races, specifically, so that the stepwhich is indicated by δ (=(ICD−IBD)/2) or Δ(=(OBD−OCD)/2) in the figurehas a value that is predetermined for each of the races. As result ofthe process, the dimensions IBD and OBD of the rolling bearing racewaysurfaces 1 a and 2 a are matched in accordance with the ball diameter Bdso as to obtain an adequate initial radial gap which enables a desiredradial gap to be obtained after the inner race 1 and the outer race 2are incorporated into the respective counterparts. According to theconfiguration, an adequate initial J space which enables a desired Jspace to be obtained after incorporation.

According to the method, when the diameter of balls serving as therolling elements is indicated by Bd and the radial gap between therolling bearing raceway surface and the ball rolling surface isindicated by Tr, the J space after the inner race 1 and the outer race 2are incorporated into the counterparts is given by:J space=Bd+Tr/2−(δ+Δ)  (1)Namely, the J space is constant, and it is not required to change thedimension of the one-way clutch raceway surface depending on thecounterpart.

In order to easily realize a process in which the step differences δ andΔ between the rolling bearing raceway surfaces 1 a and 2 a of the innerrace and the outer race, and the one-way clutch raceway surfaces 1 b and2 b are constant, it is preferable to employ a form grinding processusing a rotary dresser as in the invention of claim 11. When such a formgrinding process is employed, the shape of the rotary dresser istransferred to a workpiece via a grinding wheel, and hence the steps δand Δ are always constant irrespective of cutting by the grinding wheel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a first embodiment of theinvention;

FIG. 2 is a side view of the first embodiment of the invention,partially cutting away a side plate;

FIG. 3 is a section view taken along the line A-A of FIG. 2;

FIG. 4A is a perspective view illustrating a first annular member 51constituting a cage 5 in the first embodiment of the invention, and FIG.4B is an enlarged view looking in the direction of the arrow B;

FIG. 5A is a perspective view illustrating a second annular member 52constituting the cage 5 in the first embodiment of the invention, andFIG. 5B is an enlarged view looking in the direction of the arrow B;

FIG. 6 is a partially cutaway front view of a second embodiment of theinvention;

FIG. 7 is a section view taken along the line A-A of FIG. 6;

FIG. 8 is a partial enlarged view of FIG. 7;

FIG. 9 is an axial section view of a third embodiment of the inventionset forth in claim 6;

FIG. 10 is an axial section view of an embodiment of the invention setforth in claim 8;

FIG. 11 is a view illustrating a method of grinding an outer peripheralface of an inner race 1 in a fourth embodiment of the invention;

FIG. 12 is a view illustrating a method of grinding an inner peripheralface of an outer race in the fourth embodiment of the invention;

FIG. 13A is a view illustrating relationships between the dimensions ofa rolling bearing raceway surface 1 a and a one-way clutch racewaysurface 1 b of the inner race 1 in the fourth embodiment of theinvention after grinding, and FIG. 13B is a view illustratingrelationships between the dimensions of a rolling bearing racewaysurface 2 a of the outer race 2 and a one-way clutch raceway surface 2b;

FIG. 14 is a partially cutaway front view showing a configurationexample of a conventional one-way clutch integrated with a rollingbearing;

FIG. 15 is an axial section view looking in the direction of A-A in FIG.14 showing an example of a conventional one-way clutch integrated with arolling bearing in which a one-way clutch is disposed on each of thesides of a ball bearing;

FIG. 16 an exploded perspective view of a cage 65, and spring and sideplates 66 in the conventional example of FIG. 15;

FIG. 17 is a section view of main portions of the conventional exampleof FIG. 16 in a state where two annular members 651 and 652 constitutingthe cage 65 are engaged with each other;

FIG. 18 is an axial section view showing a configuration example of aconventional one-way clutch integrated with a rolling bearing;

FIG. 19 is an axial section view showing a configuration example of aconventional one-way clutch integrated with a rolling bearing which isimproved so as to widen the J space; and

FIG. 20A is a view illustrating a method of controlling the dimensionsof a rolling bearing raceway surface and a one-way clutch racewaysurface of an inner race of a conventional one-way clutch integratedwith a rolling bearing, and FIG. 20B is a view illustrating a method ofcontrolling the dimensions of an outer race.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, a first embodiment of the invention will be described withreference to the accompanying drawings. FIG. 1 is an explodedperspective view of the embodiment of the invention, FIG. 2 is a sideview, partially cutting away a side plate, and FIG. 3 is a section viewtaken along the line A-A of FIG. 2.

A raceway surface 1 a for a deep groove ball bearing, and a racewaysurface 1 b for a one-way clutch are formed axially adjacent to eachother in the outer peripheral face of an inner race 1. Opposing to theraceway surfaces, a raceway surface 2 a for a deep groove ball bearing,and a raceway surface 2 b for a one-way clutch are formed on the innerperipheral face of an outer race 2. Plural balls 3 serving as rollingelements are arranged between the inner race 1 and the outer race 2 soas to make rolling contact with both the raceway surfaces 1 a and 2 afor a deep groove ball bearing, and plural sprags 4 are arranged so asto tiltably make contact with the raceway surfaces 1 b and 2 b for aone-way clutch.

A cage 5 which holds the balls 3 and the sprags 4 at predeterminedpitches in the circumferential direction is placed between the innerrace 1 and the outer race 2. The cage 5 is configured by engaging andintegrating first and second annular members 51 and 52 with each otherin the axial direction. Recesses 51 a and 52 a the numbers of which areequal to each other are formed in opposed positions of the annularmembers 51 and 52. In the engagement state, ball pockets are formed bythe recesses 51 a and 52 a. An annular flat plate portion 51 b is formedon the side of the face which is opposite to the face of the firstannular member 51 a in which the recesses 51 a are formed. The inner andouter peripheries of the flat plate portion 51 b are opposed to theouter peripheral face of the inner race 1, and the inner peripheral faceof the outer race 2 via small gaps, respectively. One axial end side ofthe annular space between the inner race 1 and the outer race 2 issealed by the flat plate portion 51 b. Plural sprag pockets 52 b forrespectively housing the sprags 4 are formed in the side of the secondannular member 52 which is opposite to the recesses 52 a.

On the side of the other axial end of the annular space between theinner race 1 and the outer race 2, i.e., the end on the side where thesprags 4 are arranged, a spring and side plate 6 in which plural springpieces 6 b for urging the sprags 4 in a locking direction are integrallyformed is fixed to the second annular member 52.

FIG. 4A is a perspective view illustrating the first annular member 51constituting the cage 5, and FIG. 4B is an enlarged view looking in thedirection of the arrow B. FIG. 5A is a perspective view illustrating thesecond annular member 52, and FIG. 5B is an enlarged view looking in thedirection of the arrow B.

In the first annular member 51, engagement portions 51 c which axiallyprotrude are respectively formed between the recesses 51 a for ballpockets, and a guide groove 51 d which axially elongates is formed ineach of the engagement portions 51 c. A radial through hole 51 e whichpasses in a radial direction of the first annular member 51 is formed inthe inner side of the guide groove 51 d (the basal end side of theengagement portion 51 c). The inner side of the guide groove 51 dcommunicates with the radial through hole 51 e.

By contrast, in the second annular member 52, claws 52 c which protrudein the axial direction are respectively formed between the ball pocketrecesses 52 a. In each of the claws 52 c, an inclined face 52 d isformed in the tip end, and an engaging portion 52 e is formed in thebasal end of the inclined face 52 d. An axial through hole 52 f whichaxially passes is formed in the root portion of the claw 52 c.

The two annular members 51 and 52 are integrated with each other in thefollowing manner. In a state where the guide grooves 51 d and the claws52 c are opposed to one another and their centers are substantiallycoincident with one another, the claws 52 c are inserted into the guidegrooves 51 d, respectively. When the engaging portions 52 e of the claws52 c then reach the respective radial through holes 51 e communicatingwith the inner sides of the guide grooves 51 d, the annular members aresurely engaged and integrated with each other in such a manner that theyare unseparable in a usual use state.

The thus configured first and second annular members 51 and 52 areproduced by injection molding of a resin. In the first annular member51, the radial through holes 51 e communicating with the inner sides ofthe guide grooves 51 d are formed as undercuts, and, in the secondannular member 52, the engaging portions 52 e formed in the basalportions of the claws 52 c are formed as undercuts. When a split moldwhich radially moves is used, the radial through holes 51 e can bemolded with using the radial through holes 51 e themselves as extractingholes for the split mold, and the engaging portions 52 e can be moldedwith using the axial through holes 52 f as mold extracting holes.

The embodiment of the invention can be assembled in the followingmanner. In a state where the outer race 2 is placed on the outside ofthe inner race 1, a required number of balls 3 are arranged between therolling bearing raceway surfaces 1 a and 2 a at substantially constantintervals in the circumferential direction. Under this state, the firstand second annular members 51 and 52 are inserted between the inner race1 and the outer race 2 from the both axial sides so as to sandwich theballs 3, and the claws 52 c are respectively inserted into the guidegrooves 51 d to be engaged and integrated with each other. In thisstate, the annular space between the inner race 1 and the outer race 2is sealed in the end portion on the side of the first annular member 51by the flat plate portion 51 b of the first annular member 51, and, inthe opposite side, the axial through holes 52 f formed in the secondannular member 52 are opened. When grease is then poured via the axialthrough holes 52 f in this state, the space between the rolling bearingraceway surfaces 1 a and 2 a can be easily filled with the grease.Thereafter, the sprags 4 are inserted into the sprag pockets 52 b formedin the second annular member 52, respectively, and the spring and sideplate 6 is attached. In this sate, the spring and side plate 6 coversthe axial through holes 52 f to seal the end portion of the annularspace between the inner race 1 and the outer race 2 on the side of thesecond annular member 52. Therefore, the grease does not leak.

In the use state, the existence of the radial through holes 51 e formedin the first annular member 51 allows the grease to freely flow betweenthe inner race 1 and the outer race 2, and the life can be expected tobe prolonged by the improved lubrication performance.

In the above, the embodiment in which a ball bearing is used as therolling bearing has been described. Alternatively, a rolling bearing ofanother kind such as a roller bearing may be used.

As described above, according to the invention, in a one-way clutchintegrated with a rolling bearing in which a one-way clutch is placed onone side of rolling bearing, a cage for holding rolling elements andsprags is structured by engaging two annular members with each other, aflat plate portion which seals the annular space between inner and outerraces is disposed on one of the annular members, a radial through holewhich passes in a radial direction is formed in the one annular member,and an axial through hole which passes in the axial direction is formedin the other annular member. Therefore, the workability of theassembling process including the grease filling work can be improved,and, also during use, the grease has an excellent flowability and thelubrication performance is improved. This contributes to the prolongedlife.

The axial through hole and the radial through hole can be used in moldextraction for forming undercuts which are disposed in engaging portionsof each of the annular members. Therefore, a cage which is hardly spliteven by an application of an impact load or the like can be obtained.

A second embodiment of the invention will be described with reference tothe accompanying drawings.

FIG. 6 is a partially cutaway front view of the embodiment of theinvention, FIG. 7 is a section view taken along the line A-A of FIG. 6,and FIG. 8 is a partial enlarged view of FIG. 7.

A raceway surface 1 a for a deep groove ball bearing, and a racewaysurface 1 b for a one-way clutch are formed axially adjacent to eachother in the outer peripheral face of an inner race 1. Opposing to theraceway surfaces, a raceway surface 2 a for a deep groove ball bearing,and a raceway surface 2 b for a one-way clutch are formed on the innerperipheral face of an outer race 2. Plural balls 3 serving as rollingelements are arranged between the inner race 1 and the outer race 2 soas to make rolling contact with both the raceway surfaces 1 a and 2 afor a deep groove ball bearing, and plural sprags 4 are arranged so asto tiltably make contact with the raceway surfaces 1 b and 2 b for aone-way clutch.

The balls 3 and the sprags 4 are held at predetermined pitches in thecircumferential direction by a common cage 5. The cage 5 has a structurein which the first and second annular members 51 and 52 are engaged andintegrated with each other in the axial direction. In the first annularmember 51, plural engaging portions 51 a are formed at predeterminedpitches in the circumferential direction so as to axially protrude. Anengaging hole 51 b which passes in the axial direction is formed in eachof the engaging portions 51 a. In the second annular member 52, claws 52a are formed at the same pitches in the circumferential direction so asto axially protrude. An engaging portion 52 b is formed in each of theclaws 52 a. When the engaging portions 52 b of the claws 52 a of thesecond annular member 52 are engaged with the engaging holes 51 b of thefirst annular member 51, the first and second annular members 51 and 52are engaged and integrated in the axial direction with each other,whereby the cage 5 is formed.

An annular flat plate portion 51 c is integrally formed on an axial endside of the first annular member 51. The inner and outer peripheries ofthe plate portion 51 c are opposed to the outer peripheral face of theinner race 1, and the inner peripheral face of the outer race 2 viasmall gaps, respectively. One axial end side of the annular spacebetween the inner race 1 and the outer race 2 is sealed by the flatplate portion 51 c.

A spring and side plate 6 is attached to the axial outer side of thesecond annular member 52. In the spring and side plate 6, as shown inFIG. 6, spring pieces 6 b are integrally formed at predetermined pitchesin the circumferential direction on a base member 6 a formed by anannular flat plate. The base member 6 a seals the other axial end sideof the annular space between the inner race 1 and the outer race 2, andthe spring pieces 6 b urge the sprags 4 in a locking direction,respectively.

Between one of the shoulder portions of the raceway surface 1 a for adeep groove ball bearing of the inner race 1, i.e., the shoulder 1 c onthe side of the one-way clutch raceway surface 1 b, and the one-wayclutch raceway surface 1 b, formed is a step 10 that is directed in adirection in which the diameter (outer diameter) of the one-way clutchraceway surface 1 b becomes smaller. Between one of the shoulderportions of the raceway surface 2 a for a deep groove ball bearing ofthe outer race 2, i.e., the shoulder 2 c on the side of the one-wayclutch raceway surface 2 b, and the one-way clutch raceway surface 2 b,formed is a step 20 that is directed in a direction in which thediameter (inner diameter) of the one-way clutch raceway surface 2 bbecomes larger.

According to the configuration, the J space (indicated by J in FIG. 8)between the one-way clutch raceway surface 1 b of the inner race 1, andthe one-way clutch raceway surface 2 b of the outer race 2 is wider thanthat in the conventional art, with the result that the sprags 4 of alarger size can be used.

As indicated by the two-dot chain line in FIG. 7, the embodiment of theinvention is used while the inner diameter surface of the inner race 1is fitted to a shaft S and the outer diameter surface of the outer race2 is fitted to a housing H. Usually, these fits are realized by aninterference fit so as to disable a relative rotation with respect tothe fitting counterparts. Since the steps 10 and 20 are formed, theradial thicknesses of the portions of the inner race 1 and the outerrace 2 where the one-way clutch raceway surfaces 1 b and 2 b are formedare reduced. As a result of this thinning, there arises the possibilitythat the inner race 1 or the outer race 2 follows the shape of thefitting surface of the corresponding counterpart. In the case where theshape accuracy is poor, there is the possibility that also the shapeaccuracy the one-way clutch raceway surface 1 b or 2 b is impaired. Tocomply with this, in the inner race 1 or the outer race 2 which is onthe side of one of the counterparts or the shaft S and the housing Hthat has higher shape accuracy of the fitting surface, the height of thestep is increased, whereby the shape accuracy is prevented from exertingan influence. Usually, the shape accuracy of the fitting surface of theshaft S is higher. In this case, therefore, the step 10 of the innerrace 1 is set to be larger than the step 20 of the outer race 2, wherebythe portion of the inner race 1 where the one-way clutch raceway surface1 b is formed is made thinner, and that of the outer race 2 where theone-way clutch raceway surface 2 b is formed is made thicker. Accordingto the configuration, the shape accuracies of both the one-way clutchraceway surfaces 1 b and 2 b can be kept excellent while ensuring adesired J space.

In the above, the embodiment in which a deep groove ball bearing is usedas the rolling bearing has been described. It is a matter of course thata rolling bearing of another kind may be used.

In the embodiment described above, the structure in which the twoannular members 51 and 52 are engaged and integrated with each other inthe axial direction is used as the cage 5. Alternatively, as shown inFIG. 18, a cage for a rolling bearing and that for a one-way clutch maybe separately formed, or, as shown in FIG. 19, an integral cage may beused. It is a matter of course that, in place of the spring and sideplate used in the embodiment, other known means such as a garter springshown in FIG. 18 may be used as a spring for urging a sprag of a one-wayclutch.

As described above, according to the invention, in each of the innerrace and the outer race, the step is formed between the shoulder of therolling bearing raceway surface and the one-way clutch raceway surface,whereby the J space formed between the one-way clutch raceway surfacesof the inner and outer races can be made wider than the dimension formedby the shoulder of the rolling bearing raceway surface. According to theconfiguration, larger sprags can be used, and the performance includingthe transmission torque can be improved without causing the whole sizeto be increased as compared with a conventional one. In one of the innerand outer races which is on the side of a counterpart having a highershape accuracy of the fitting surface, the step of the race is madelarger, whereby degradation of the shape of the one-way clutch racewaysurface which is caused by following to the counterpart due to thethickness reduction can be prevented from occurring.

Next, a third embodiment of the invention will be described withreference to the accompanying drawings.

FIG. 9 is an axial section view of an embodiment of the invention setforth in claim 6, and showing a state where the embodiment isincorporated to a shaft S and a housing H.

A one-way clutch integrated with a rolling bearing of the embodimentcomprises: an inner race 1; an outer race 2; plural balls 3 which arerollably arranged between the races; plural sprags 4; a ball cage 5which holds the balls 3 at constant pitches in the circumferentialdirection; a sprag cage 6 which holds the sprags 4 at constant pitchesin the circumferential direction; a spring member 6 in which pluralspring pieces 6 b for urging the sprags 4 in a locking direction areintegrally formed on an annular base member; and seals 8 and 9 forsealing both the axial ends. The shaft S is fitted to the innerperipheral face of the inner race 1, and the outer peripheral face ofthe outer race 2 is fitted to the housing H.

The embodiment is characterized in that a rolling bearing racewaysurface 2 a and a one-way clutch raceway surface 2 b are formed on theouter race 2, but only a rolling bearing raceway surface 1 a is formedon the inner race 1, and the inner peripheral sides of the sprags 4 arein direct contact with the surface of the shaft S, and also that thewidth (axial dimension) of the inner race 1 is smaller than that of theouter race 2, and fails to reach positions where the sprags 4 areplaced.

In the same manner as a conventional one-way clutch of this kind, therolling bearing raceway surface 2 a on which the balls 3 roll, and theone-way clutch raceway surface 2 b which extends adjacent to and inparallel with the rolling bearing raceway surface 2 a, and with whichthe outer peripheral sides of the sprags 4 are in contact are formed onthe inner periphery of the outer race 2. By contrast, only the rollingbearing raceway surface 1 a on which the balls 3 roll is formed on theouter periphery of the inner race 1, and the width (axial dimension) ofthe inner race 1 is smaller than that of the outer race 2, and fails toreach the positions where the sprags 4 are placed. In each of the sprags4, the outer peripheral side is in contact with the one-way clutchraceway surface 2 b formed on the outer race 2, and the inner peripheralside is in direct contact with the outer peripheral face of the shaft S,so that the outer peripheral face of the shaft S substantially forms aninner one-way clutch raceway surface S_(TC).

In the shaft S, the outer diameter of the portion SF which is fitted tothe inner race 1 is equal to that of the portion with which the innerperipheral sides of the sprags 4 are in contact, i.e., that where theone-way clutch raceway surface S_(TC) is formed.

In the embodiment described above, the J space which is the distancebetween the raceway surfaces of the inner and peripheral sides in thesprags 4 can be widened by a dimension corresponding to the thickness ofthe inner race 1 as compared with a conventional case. As a result, theperformance such as the transmission torque can be improved. The sprags4 conduct torque transmission between the outer race 2 and the shaft S.Even when the fitting between the inner race 1 and the shaft S is set tobe looser than that in a conventional case, therefore, it is possible toeliminate reduction of the torque transmission due to occurrence ofslippage between the two members, and the work of attaching the one-wayclutch to the shaft S and the housing H can be further simplified ascompared with a conventional case.

Next, an embodiment of the invention set forth in claim 8 will bedescribed. FIG. 10 is an axial section view of the embodiment.

The embodiment is characterized in that a rolling bearing racewaysurface 11 a and a one-way clutch raceway surface 11 b are formed on aninner race 11, but only a rolling bearing raceway surface 12 a is formedon an outer race 12, and the outer peripheral sides of sprags 14 are indirect contact with the inner peripheral face of the housing H.

The rolling bearing raceway surface 11 a on which balls 13 roll, and theone-way clutch raceway surface 11 b which extends adjacent to and inparallel with the rolling bearing raceway surface 11 a, and with whichthe inner peripheral sides of the sprags 14 are in contact are formed onthe outer periphery of the inner race 11. By contrast, only the rollingbearing raceway surface 12 a on which the balls 13 roll is formed on theinner periphery of the outer race 12, and the width of the outer race 12is smaller than that of the inner race 11, and fails to reach thepositions where the sprags 14 are placed. In each of the sprags 14, theinner peripheral side is in contact with the one-way clutch racewaysurface 11 b formed on the inner race 11, and the outer peripheral sideis in direct contact with the inner peripheral face of the housing H, sothat the inner peripheral face of the housing H substantially forms aninner one-way clutch raceway surface H_(TC).

In the housing H, the inner diameter of the portion H_(F) which isfitted to the outer race 12 is equal to that of the portion with whichthe outer peripheral sides of the sprags 14 are in contact, i.e., thatwhere the one-way clutch raceway surface H_(TC) is formed.

In the embodiment, the balls 13 and the sprags 14 are held by a commoncage 15. The cage 15 has a structure in which first and second annularmembers 15 a and 15 b are engaged and integrated with each other in theaxial direction. In the first annular member 15 a, plural engagingportions 150 are formed at constant pitches in the circumferentialdirection so as to axially protrude. An engaging hole 151 which passesin a radial direction is formed in each of the engaging portions 150. Inthe second annular member 15 b, claws 152 are formed at the same pitchesin the circumferential direction so as to axially protrude. An engagingportion 153 is formed in each of the claws 152. When the engagingportions 153 of the claws 152 of the second annular member 15 b areengaged with the engaging holes 151 of the first annular member 15 a,the first and second annular members 15 a and 15 b are engaged andintegrated in the axial direction with each other, whereby the cage 15is formed.

In the embodiment, a flat plate portion 154 is integrally formed on oneaxial end side of the first annular member 15 a constituting the cage15. The flat plate portion 154 functions as a seal for the axial endside. In the same manner as the embodiments described above, a structurein which plural spring pieces (not shown in FIG. 10) are formedintegrally on an annular base member 16 a is used as a spring member 16which urges the sprags 14 in the locking direction. The spring member 16is fixed to the cage 15, and the base member 16 a has a function ofsealing the other axial end side.

In the embodiment described above, the J space which is the distancebetween the raceway surfaces of the inner and outer peripheral sides ofthe sprags 14 can be widened by a dimension corresponding to thethickness of the outer race 12 as compared with a conventional case. Asa result, the performance such as the transmission torque can beimproved. The sprags 14 conduct torque transmission between the innerrace 11 and the housing H. Even when the fitting between the outer race12 and the housing H is set to be looser than that in a conventionalcase, therefore, it is possible to eliminate reduction of the torquetransmission due to occurrence of slippage between the two members, andthe work of attaching the one-way clutch to the shaft S and the housingH can be further simplified as compared with a conventional case.

According to the invention set forth in claim 6, the one-way clutchraceway surface is integrally formed only on the outer race of therolling bearing, the outer peripheral sides of the sprags make contactwith the one-way clutch raceway surface, and the inner peripheral sidesof the sprags are not in contact with the inner race but are in directcontact with the outer peripheral face of the shaft to which the innerrace of the rolling bearing is fitted, thereby causing the sprags totransmit a torque between the one-way clutch raceway surface which isformed on the inner periphery of the outer race, and the outerperipheral face of the shaft. Therefore, the J space can be widened andthe performance such as the transmission torque can be improved ascompared with a conventional case where a rolling bearing racewaysurface and a one-way clutch raceway surface are integrally formed onboth inner and outer races and sprags transmit a torque between theinner and outer races.

According to the invention set forth in claim 8, the one-way clutchraceway surface is integrally formed only on the inner race of therolling bearing, the inner peripheral sides of the sprags make contactwith the one-way clutch raceway surface, and the outer peripheral sidesof the sprags are not in contact with the outer race but are in directcontact with the inner peripheral face of the housing to which the outerrace of the rolling bearing is fitted, thereby causing the sprags totransmit a torque between the one-way clutch raceway surface which isformed on the outer periphery of the inner race, and the innerperipheral face of the housing. In the same manner as described above,therefore, the J space can be widened and the performance such as thetransmission torque can be improved as compared with a conventionalcase.

In the inventions described above, the sprags transmit a torque betweenthe outer race and the shaft, or between the inner race and the housing,and hence the race (the inner race in claim 6, and the outer race inclaim 8) on which only the rolling bearing raceway surface is formed iseliminated from the torque transmission path. Unlike the conventionalart, the fitting between the race and the shaft or the housing is notrequired to be tight. As a result, the race can be fitted more looselyto the shaft or the housing as compared with the conventional art, andthe workability of the assembling process is improved.

As the invention set forth in claim 7 or 9, when a configuration wherethe outer diameter of a portion of the shaft with which the sprags makecontact is equal to the outer diameter of a portion which is fitted tothe inner race of the rolling bearing, or that where the inner diameterof a portion of the housing with which the sprags make contact is equalto the inner diameter of a portion to which the outer race of therolling bearing is fitted is employed, the above-mentioned effects canbe attained without affecting the other performances required in theshaft or the housing, and increasing the production cost of the shaft orthe housing.

Next, a fourth embodiment of the invention will be described withreference to the accompanying drawings. A method of producing a one-wayclutch integrated with a rolling bearing having a structure which isidentical with that shown in FIGS. 14 and 15 will be described.

FIG. 11 is a view illustrating a method of grinding a rolling bearingraceway surface 1 a and a one-way clutch raceway surface 1 b of an innerrace 1 of the embodiment of the invention, and FIG. 12 is a viewillustrating a method of grinding a rolling bearing raceway surface 2 aand a one-way clutch raceway surface 2 b of an outer race 2 of theembodiment of the invention.

In the inner race 1 and the outer race 2, the rolling bearing racewaysurfaces 1 a and 2 a, and the one-way clutch raceway surfaces 1 b and 2b are simultaneously ground by a form grinding process using a grindingwheel 102 or 202 which is shaped by a rotary dresser 101 or 201.

In a process of grinding the inner race 1, specifically, a knownexternal cylindrical grinding machine such as a microcentric machine isused. As shown in FIG. 11A, toothing and shaping are simultaneouslyconducted on the grinding wheel 102 by the rotary dresser 101 which isprovided with a shape equivalent to the outer peripheral face of theinner race 1 after the grinding process. As a result, the outerperipheral face of the grinding wheel 102 is formed into a negativeshape of the outer peripheral face of the inner race 1. When incision isconducted under the state where the grinding wheel 102 is shaped in thisway, both the rolling bearing raceway surface 1 a and the one-way clutchraceway surface 1 b are simultaneously ground in the outer peripheralface of the inner race 1 as shown in FIG. 11B. In the inner race 1 afterthe grinding process, as shown in FIG. 13A, the difference between thediameter IBD of the rolling bearing raceway surface 1 a and the diameterICD of the one-way clutch raceway surface 1 b, or the step indicated byδ in the figure is always constant.

In a process of grinding the outer race 2, an internal cylindricalgrinding machine is used. In this process also, as shown in FIG. 12A,toothing and shaping are simultaneously conducted on the grinding wheel202 by the rotary dresser 201 which is provided with a shape equivalentto the inner peripheral face of the outer race 2 after the grindingprocess. As a result, the outer peripheral face of the grinding wheel202 is formed into a negative shape of the inner peripheral face of theouter race 2. When incision is conducted under the state where thegrinding wheel 202 is shaped in this way, both the rolling bearingraceway surface 2 a and the one-way clutch raceway surface 2 b aresimultaneously ground in the inner peripheral face of the outer race 2as shown in FIG. 12B. In the outer race 2 after the grinding process, asshown in FIG. 13B, the difference between the diameter OBD of therolling bearing raceway surface 2 a and the diameter OCD of the one-wayclutch raceway surface 2 b, or the step indicated by Δ in the figure isalways constant.

In the inner race 1 and the outer race 2 which have been subjected to agrinding process with using a rotary dresser as described above, therolling bearing raceway surfaces 1 a and 2 a are superfinished.Thereafter, the inner and outer races are subjected to an assemblingprocess. In the assembling process, in order to obtain a desired radialgap Tr after deformation due to the dimensions of counterparts to whichthe inner race 1 and the outer race 2 are to be fitted, the rollingbearing raceway surfaces 1 a and 2 a of the inner race 1 and the outerrace 2 are measured, and a combination that enables an initial radialgap in which the deformation is considered is selected.

In the one-way clutch integrated with a rolling bearing which isassembled by the method, the J space of the one-way clutch after theinner race 1 and the outer race 2 are incorporated into the counterpartsis given by expression (1) above, and always substantially constantbecause (δ+Δ) is constant.

According to the production method, in the inner race 1 and the outerrace 2, therefore, it is substantially unnecessary to inspect andcontrol the dimensions of the one-way clutch raceway surfaces 1 b and 2b, and it is requested only to control the dimensions of the rollingbearing raceway surfaces 1 a and 2 a. Even when only matching requiredin a rolling bearing is conducted, not only the radial gap of therolling bearing but also the J space has a designed value.

In the above embodiments, a one-way clutch integrated with a rollingbearing in which a one-way clutch is disposed on one axial side of arolling bearing has been described. It is a matter of course that theinvention can be similarly applied also to a structure in which aone-way clutch is disposed on each of the axial sides of a rollingbearing.

As described above, according to the invention, with respect to bothinner and outer races, it is not required to produce one-way clutchraceway surfaces which have plural different kinds of dimensions inaccordance with counterparts. Therefore, the number of steps ofinspecting and controlling the dimensions of the one-way clutch racewaysurface can be reduced, and the production cost can be lowered.

1. A one-way clutch integrated with a rolling bearing in which a spragone-way clutch is integrally formed on a side of a rolling bearing,wherein a one-way clutch raceway surface with which outer peripheralsides of sprags of said one-way clutch make contact is integrally formedon an axial side of a raceway surface of an outer race of said rollingbearing, and inner peripheral sides of said sprags are to make contactwith an outer peripheral face of a shaft which is to be fitted to aninner peripheral face of an inner race of said rolling bearing, therebyconducting torque transmission between said outer peripheral face ofsaid shaft and said one-way clutch raceway surface of said outer race.2. A one-way clutch integrated with a rolling bearing according to claim1, wherein an outer diameter of a portion of said shaft with which theinner peripheral sides of said sprags are to make contact isapproximately equal to an outer diameter of a portion to which saidinner peripheral face of said inner race of said rolling bearing is tobe fitted.
 3. A one-way clutch integrated with a rolling bearing inwhich a sprag one-way clutch is integrally formed on a side of a rollingbearing, wherein a one-way clutch raceway surface with which innerperipheral sides of sprags of said one-way clutch make contact isintegrally formed on an axial side of a raceway surface of an inner raceof said rolling bearing, and outer peripheral sides of said sprags areto make contact with an inner peripheral face of a housing to which anouter peripheral face of an outer race of said rolling bearing is to befitted, thereby conducting torque transmission between said innerperipheral face of said housing and said one-way clutch raceway surfaceof said inner race.
 4. A one-way clutch integrated with a rollingbearing according to claim 3, wherein an inner diameter of a portion ofsaid housing with which the outer peripheral sides of said sprags are tomake contact is approximately equal to an inner diameter of a portion towhich said outer peripheral face of said outer race of said rollingbearing is to be fitted.